Gwynne Anthony 2020

ART506 Dissertation 2019. Anthony Gwynne . 112 a suitably qualified and experienced conservation specialist- suitable for the type of wall material and degree of exposure. Guidance Table 5: Compressive strengths for lime Type of lime Typical compressive strength (N/mm 2 ) (tested at 28 days- greater strengths achieved thereafter) Traditional Fat Lime (non hydraulic)* 0.3 - 0.5 Hydraulic lime* NHL 2 NHL 3.5 NHL 5 Limecrete floors 1.3 - 2.0 2.0 - 4.5 5.0 - 10.0 4.0 (increases to 6.5 at 56 days and 8.3 at 90 days) Notes: * Increased strength reduces permeability and flexibility. Haired lime plaster Hair/fiber (typically goats/ horse hair or synthetic hair or other approved at 1.5kg per tonne) to provide tensile strength where necessary, cut into 50mm lengths and added (teased) into the mix to the proportion/ratio as specified by a suitably qualified and experienced conservation specialist. Note: Synthetic hair is often used in premixed plasters as natural hair will degrade in un-carbonated lime after a few weeks. Pozzolanic materials for lime plaster Pozzolanic materials containing silica and alumina such as brick dust, pulverized fuel ash (PFA) and calcined clay can be added to non hydraulic lime putty (also known as fat lime) where necessary to increase the setting time similar to that of hydraulic lime. The type and ratio of pozzolanic material is to be specified by a suitably qualified and experienced conservation specialist.